I agree with everyone that if you don't want to ride him, then IMO you shouldn't. But from the point of view of his health & soundness, more work(& less lunging circles) would likely be good for him.... depending on the specifics.
Comfort is of primary importance IMO and if he's kept well trimmed & you can boot him, keep him on yielding surfaces, etc, so that he can comfortably use his feet *correctly*, then go for it. I would hesitate to work him on hard or flat surfaces if his walls are weightbearing however and would also pad his feet to comfortably support the sole/frog(& reduce any pressure on walls) when on unyielding flat ground.
At a year & a half since the laminitis 'attack', if his feet aren't yet in good shape, I would hazard a guess that it was far more than just 'an attack' - it was probably the final straw of an unrecognised ongoing chronic situation. There are many other factors, including diet & exercise, that influence how quickly/slowly things may improve. Eg you say his weight's good now, but if it wasn't until a few months ago, or he's still getting rich feed or such, he may have been still suffering ongoing lami due to insulin resistance or some such. However, if your farrier has effectively trimmed in order to remove the leverage & excess pressure from the disconnected walls, then so long as his soles are padded for comfort/protection, the horse *generally speaking of course* should be able to work & even carry you soon after the 'event'.
Of course, remember the above - & any other opinions you get - are just that and based on only a little info from you. So don't take anything as 'fact', but do your own homework, learn as much as you can & consider the opinions you get, to try to make the best most informed choices. On that note, hoofrehab.com is one good source for you to learn more. You could also post hoof pics here, if you'd like more specific opinions. Good Hoof Photos - How to take Good Hoof Photos
is a good source for learning what's required for best hoof pics.